On Tue, 14 May 2013 07:22:26 +0200
Herbert Poetzl herb...@13thfloor.at wrote:
If the best-case response time is calibrated out, how good
can this get? Microseconds?
With 125us latency and a fixed interval, it should be
possible to calculate the relation between the transfer
intervall
Re: [time-nuts] OCXO shock protection
Water heaters must be bolted to the wall studs. Other wise they go over.
Several hundred pounds of water is a big mass.
Lived there for 50 years. Generally earthquakes are pretty localized and not a
huge hazard with just a little thought. You do
On Mon, 13 May 2013 12:17:42 -0700
Hal Murray hmur...@megapathdsl.net wrote:
Anybody know if uBlox over USB units are available? I just took a quick look
and didn't find anything.
IIRC all LEA-5 and newer have an USB port for communication.
I couldnt find anything in the protocol specs
Moin,
A couple of weeks ago, there was a short discussion on bad connectors
and cables and the coupled in noise of those. Summarized it said that
measurements in the time-nuts scale are very sensitive to even the lowest
noise levels and coupled in signals.
But, all the measurements we do are
I was there as well, but did not see much of interest. That might be because
Paul Swed scooped up the good stuff before I could finish the first pass :)
Nice find Paul, hope they settle down for you. Would love to see a post-flea
get together and put some faces with names, but I don't know of
Paul,
So you were there and I missed you then. It was hard to find anything.
Looking in all the corners. Most of its now the monthly repeat stuff that
doesn't seem to move.
John,
You are right it would be a TM5000 3 bay. The color is tek blue, not the
brown of the 5000 series. Funny I don't care
Try Stabilant.
http://www.amazon.com/Stabilant-5ml-Kit-Makes-30ml/dp/B001E50GQS
I have no affiliation with this product. I've used it to fix
intermittent connections that drove me crazy. It's not a contact
cleaner, and you'll have to read the details to understand what it does.
It's also
There are cafe/pizza options in the Strattion Student Center, although
seating is somewhat limited. But there are other places in the same
building.
It's a short walk from the flea site (Mass Ave at Vasser Street) Bldg W-20
-John
I was there as well, but did not see much of
It is surprizingly difficult to find other shoppers at the Flea. I
suspoect it's because people sort of 'shop with the flow'- all moving in
the same direction.
-John
=
Paul,
So you were there and I missed you then. It was hard to find anything.
Looking in all the corners.
Plenty of good stuff in the area; Flour, Area Four, Catalyst, Friendly
Toast, Blue Room, CBC, and so on.
I live in the area - recent MIT graduate - and would be happy to set
something up (though I think my gf's birthday is that day, so maybe not)
Andy Bardagjy
bardagjy.com
On Mon, May 20, 2013
IMO, it would be good to have any gathering place w/in easy walking
distance of the flea. Parking in Cambridge is not easy in the best of
times.
YMMV,
-John
=
Plenty of good stuff in the area; Flour, Area Four, Catalyst, Friendly
Toast, Blue Room, CBC, and so on.
I live in the
On 5/20/13 2:43 AM, Attila Kinali wrote:
Oh.. and connect the whole thing to a port on the PC that does _not_
have an internal USB hub.
That's a bit of challenge, I suspect.. A casual look at the PCs I have
around here running windows all seem to have on-mobo hubs when you
check Device
A gentle reminder to keep postings to time-nuts as technical as possible, and
on-topic. The occasional mention of upcoming local events or conferences is
welcome (it's a great way to build community), but I suggest subsequent
details, follow-up, meeting arrangements, and where to get pizza
I suspect the idea is to use a port where no other devices, that is internal,
are on the hub.
Like you, I never saw a usb port not on a hub.
-Original Message-
From: Jim Lux jim...@earthlink.net
Sender: time-nuts-boun...@febo.com
Date: Mon, 20 May 2013 06:14:12
To: time-nuts@febo.com
Moin Attila,
yes ground loops can cause serious measurement problems. And solving
those could fill a hole book. Here's what I do in practical:
1.) avoid the loop
2.) if you can't, try harder to avoid it
- depending on the problem: break up the dc loop by using capacitors
(most often you only
We will be moving to southern California in the near future.
My question if for people who live in that area is do you need to do
additional shock mounting for OCXO’s because of the ongoing,
usually minor, earth tremors that take place?
Hi Perry,
Your OCXO will be fine, unless it falls on
On Mon, 20 May 2013 06:14:12 -0700
Jim Lux jim...@earthlink.net wrote:
On 5/20/13 2:43 AM, Attila Kinali wrote:
Oh.. and connect the whole thing to a port on the PC that does _not_
have an internal USB hub.
That's a bit of challenge, I suspect.. A casual look at the PCs I have
around
On Mon, 20 May 2013 07:35:18 -0700
Tom Van Baak t...@leapsecond.com wrote:
If the quake is strong, the temporal acceleration is on the order of 0.1 g.
See:
http://en.wikipedia.org/wiki/Peak_ground_acceleration
Interesting. This would mean that the usual noise in an office
environment is at
On Sat, 11 May 2013 13:50:23 -0700
Brooke Clarke bro...@pacific.net wrote:
The first article at RD magazine cites another article in Nature, but it's a
$ article.
http://www.rdmag.com/news/2013/05/flawed-diamonds-promise-sensory-perfection
Solid-state electronic spin coherence time
Attila Kinali
One effective and sure fire way to deal with ground loops is to use
a minature 1:1 50 or 200 ohm (not critical as most instruments are not matched
inputs anyway ) in the line from your distribution amplifier to the driven
device. Coilcraft has these
for both PC and SMT Just
Hi Andy,
The simplest way is to use a low pass filter with a notch capability for
the second and third harmonics.
You can find the schematic and response for 5 and 10 MHz here:
http://www.timeok.it/files/5_and_10mhz_low_pass_notch_filter.pdf
ciao,
Luciano
timeok
see: www.timeok.it
On Mon,
Several co-workers have researched this subject extensively and have published
a number of interesting papers on the subject. The other question is what is
the nature of seismic activity in general, and specifically in your area. If I
am not mistaken the force vectors can vary greatly depending
If there are plenty of them, I'd recommend dissecting one to see how
well they're made, and what sort of components are inside. If the
crystal is hermetically sealed, it's probably OK. If there are any
aluminum electrolytic caps in there, they may be no good. Most other
parts from that era
Anyone who is serious about Time and Freq has run into ground loop problems,
and finding a solution is often more Art then Science
A common solution is star grounding, Another approach is grid work grounding,
another possible solution is to isolate each instrument.
Most often some trial and
Have any tnuts used the Apple Xcode programming setup? If so, quick
comments?
tnx Don
--
Neither the voice of authority nor the weight of reason and argument
are as significant as experiment, for thence comes quiet to the mind.
De Erroribus Medicorum, R. Bacon, 13th century.
If you don't know
Hi
Coax is interesting stuff. The shielding is only good down to some lower
frequency limit. For anything practical that's going to be 100 KHz.
At the frequencies you *should* use coax at, transformer coupling is the
easy way to break the ground loop. In this era of cell phones all over the
Several years ago there was a thread on EGG RBs. But no documentation was
ever shared.
Looking at the web there seems little still. However at one time EGG might
have been a good reference and company.
Not interested in what happened to the company its in the threads.
Did anyone ever find
I assume the question is about going from 10 Mhz to 500 MHz. The
possible solutions depend on how clean the result has to be. For
counting grade use, this has been done in a number of test
instruments like the HP5345A and HP5370A that I'm familiar with, and
certainly others. If you look at the
If you are going to produce Mac or IOS apps you don't have a choice. You
pretty much have to use it.If you are building portable apps I tend to
just use terminal sessions and a text editor and GNU's autoconf to create
the .configure files.
Depends on what you are doing
On Mon, May 20, 2013
Alright, so it seems that it's possible the Symmetricom SA.22c that I've
got might be set to 9.8304MHz. That may be programmable to 10MHz, but it
might require a DDS otherwise.
Nevertheless, if the oscillator is set to 10MHz it seems the consensus is
to construct a LPF.
Luciano, thank you for
Hi Bob whats the problem at low freqs ?? I thought leakage was a function of
the size of the holesv the wavelengthor are we into braid skin effect
below 100kHz?? so as not to drag this OT a reference will suffice in answer.
Best Wishes
Alan G3NYK
- Original Message -
From: Bob
Don--
As others have offered, if you're developing for iOS or OSX, you have little
choice.
It has a comprehensive suite of tools -- for some, too comprehensive, leading
to that old adage about how to eat an elephant -- one bite at a time.
The entire Xcode suite has a large learning curve,
Hi Andy,
If it is at 9.8304 MHz, don't even consider trying to fool with anything inside.
While it does have a DDS inside, it is of the newer design where the DDS is
inside the loop that determines frequency for locking the Rubidium. It requires
a crystal, coil and firmware change to move it to
Andy -
Glad to be of some small help. A couple of remarks re your comments
John, thanks for your input, you reminded me that LFP performance often
depends on source impedance. To the MMIC amplifier, you'd be amazed what
you can do with an opamp these days. I was amazed reading the datasheet
Oh, you can do it, but you really need to know what you're doing.
As the prev poster said, it depends on what you are doing. Simple compiles are
straightforward, autoconf if its a bit more complex, use Xcode.
If you are doing work on an app that needs a GUI, Xcode makes it easy.
On May 20,
A couple of good references regarding noise minimization in electronic
systems are:
Grounding and Shielding: Circuits and Interference by Ralph Morrison
Noise Reduction Techniques in Electronic Systems by Henry W. Ott
And the old fallback has been MIL-HDB-419 volumes I and II which
mostly
Hi
The braid becomes less effective at lower frequencies due to skin effect.
Once that happens you have a magnetic loop that is not as effective at
rejecting signals as a twisted pair.
Looking at it another way, the threat signal is induced on the shield
(braid) and it penetrates to couple to
Got it. Thanks, everyone.
Don
bownes
Oh, you can do it, but you really need to know what you're doing.
As the prev poster said, it depends on what you are doing. Simple
compiles are straightforward, autoconf if its a bit more complex, use
Xcode.
If you are doing work on an app that needs
Is anyone else seeing posts to this list showing up many hours to days late?
-John
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Hi Esa,
Sorry, I haven't tracked this group for a while. Too much work :-)
You are intuitive. I expect that the TS21 is triggering on the wrong edge.
Way, way back when the TS21 was invented, we were using an external Acutime
antenna that had an open collector pps, hence falling
Same here
If you are building apps for apple you don't have any options other than to use
XcodeFor portable code just use GNU autoconf to build GCC
Sent from my iPhone
On May 20, 2013, at 1:39 PM, Chris Albertson albertson.ch...@gmail.com wrote:
If you are going to produce Mac or IOS
yes
On Mon, May 20, 2013 at 6:15 PM, J. Forster j...@quikus.com wrote:
Is anyone else seeing posts to this list showing up many hours to days
late?
-John
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Yes. My most recent post showed up many hours (maybe six or eight) after I
sent it. That was perhaps two or three weeks ago.
73,
Brent, KD0GLS, Minneapolis
On 20 May 2013, at 18:18, J. Forster wrote:
Is anyone else seeing posts to this list showing up many hours to days late?
-John
I'm not aware of any specific server issues here (the configuration is fairly
stock Debian with Mailman and Postfix) but there can be delays due to the
vagaries of the internet and there are interactions that can cause delays for
some folks and not others.
I'll keep an eye on things to see if
Yes
J. Forster wrote:
Is anyone else seeing posts to this list showing up many hours to days late?
-John
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A couple of messages posted Friday, 5/17, showed up today 5/20, just
before I posted the query.
The issue is relatively recent... since late last week.
-John
I'm not aware of any specific server issues here (the configuration is
fairly stock Debian with Mailman and
Most of you like to DIY, but this might be of interest to some.
http://www.symmetricom.com/lp/gbu/email/time-display-promo-landing-page/?emailid=GBU078_NTD_Promo_ProdPglead_source=Web
J.D.
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